roller tappet question

[srpntlair1]

I understand that they don't recommend using hydraulic roller tappets on a standard non roller cam due to strength issues, but was just curious if anyone has put this to the test?

[is_it_EVER_done?]

The reason you can't use roller lifters on a flat tappet cam (hydraulic or solid) is not because of strength, but because a standard (non roller) cam is ground  to rotate the lifters whereas a roller cam is ground to keep the lifter as straight as possible.

You're pretty much guaranteed a failure if you mix the two.

[srpntlair1]

That is understood also, but with the use of a Guide bar, or link bar  to eliminate rotation, is it in the actual grind of the lobes? I am just trying to understand it. as a strength issue, they told me the cam will break due to cast vs. forged, which I also don't understand. If you have a valve spring at lets say 220 lbs what is the difference? spring load is spring load and I would assume the push rod would be the weak point. I am just the kind of person that wants to "understand" the why's not just take it for the saying

[Chryco Psycho]

if you look at the pattern on any flat tappet cam the lifter on touches the lobe on 1 side to rotate the lifter , the only place the lobe goes to full contact is near & over the top of the lobe , this would cause excessive stress on the guide bar as most of the time the cam would be trying to force the lifter to rotate